The invention relates to a device for cooling an interior of a motor vehicle.
A device of this kind for interior cooling is known from DE 198 38 880 and has a primary refrigerating circuit, which comprises a compressor, a condenser, an expansion element and an evaporator. The evaporator transfers the cold (i.e., a temperature conditioned flow mass such as vapor) produced in the primary circuit by the evaporator to a refrigerating medium in a secondary circuit. The secondary circuit has a main circuit and an auxiliary circuit, which are coupled by a four-way valve, allowing an adjustable proportion of the flow of refrigerating medium to be diverted from the main circuit and fed into the auxiliary circuit. Arranged in the auxiliary circuit is a heat transfer device, which is used to cool the air to be fed to the vehicle""s interior.
Also provided in the auxiliary circuit is a circulation pump. This ensures that there is always a high mass flow in the auxiliary circuit comprising the four-way valve, the feed, the heat transfer device and the return, it being possible to control the high mass flow independently of the mass flow of refrigerating medium in the main circuit, i.e. independently of the position of the four-way valve. If, for example, only a low refrigerating capacity is required, the four-way valve is set in such a way that only a small proportion of the very cold mass flow of refrigerating medium is diverted from the main circuit and fed into the auxiliary circuit. This small proportion is fed back into the main circuit via the return. If there were no circulation pump, the mass flow of refrigerating medium in the auxiliary circuit would be low in accordance with the proportion fed in through the four-way valve, and the refrigerating medium would flow only slowly through the heat transfer device. This would have the disadvantage that the refrigerating medium, which is very cold in the feed, could cause icing of the heat transfer device, at least in the region of an inlet of the heat transfer device. The air cooled by the heat transfer device would at least be very xe2x80x9cstratifiedxe2x80x9d, i.e. exhibit a large temperature difference over the cross section of an air outlet region of the heat transfer device. The high susceptibility to gradients that causes this stratification and icing, i.e. a large temperature gradient of the refrigerating medium in the auxiliary circuit, is avoided by the high mass flow that can be achieved by means of the circulation pump. However, an additional circulation pump in the auxiliary circuit is very costly since it leads to costs for materials and requires a suitable means of control.
Based on this prior art, it is the object of the invention to provide an improved device for cooling an interior, in particular one that can be produced at lower cost.
In accomplishing the objects of the invention, there has been provided, according to one aspect of the invention, a device for cooling a vehicle interior comprising a cooling device for cooling an interior of a vehicle, comprising:
a primary refrigerating circuit comprising an evaporator for providing a temperature conditioned flow; and
a secondary circuit operatively coupled to said primary refrigerating circuit, said secondary circuit carrying a refrigerating medium to which the temperature conditioned flow from said evaporator is provided, said secondary circuit comprising:
a main circuit;
an auxiliary circuit operatively coupled with said main circuit; and
an adjustable valve for controlling flow of the refrigerating medium between said main circuit and said auxiliary circuit,
wherein said auxiliary circuit comprises (i) at least one heat transfer device for receiving said refrigerating medium and cooling air to be feed into the vehicle interior, and (ii) an inner heat exchanger operatively coupled with said heat transfer device for increasing the temperature of the refrigerating medium provided to said heat transfer device.
According to another aspect of the present invention, there is provided a device for cooling comprising a vehicle air conditioning unit comprising:
a cooling device comprising:
a primary refrigerating circuit comprising an evaporator for providing a temperature conditioned flow; and
a secondary circuit operatively coupled to said primary refrigerating circuit, said secondary circuit carrying a refrigerating medium to which the temperature conditioned flow from said evaporator is provided, said secondary circuit comprising:
a main circuit;
an auxiliary circuit operatively coupled with said main circuit; and
an adjustable valve for controlling flow of the refrigerating medium between said main circuit and said auxiliary circuit,
wherein said auxiliary circuit comprises (i) at least one heat transfer device for receiving said refrigerating medium and cooling air to be feed into the vehicle interior, and (ii) an inner heat exchanger operatively coupled with said heat transfer device for increasing the temperature of the refrigerating medium provided to said heat transfer device.
In accordance with an additional aspect of the invention, there is provided a method of air conditioning air in a vehicle, comprising the steps of:
providing a temperature conditioned flow from an evaporator of a primary refrigerating circuit to a refrigerating medium flowing in a secondary refrigerating circuit;
feeding said refrigerating medium to an inner heat exchanger positioned in said secondary circuit;
heating said refrigerating medium by said inner heat exchanger;
providing said heated refrigerating medium via a feed to a heat transfer device; and
cooling said refrigerating medium by said heat transfer device.
Further objects, features and advantages of the present invention will become apparent from the detailed description of preferred embodiments that follows when considered together with the accompanying drawings.